Although radiation has proven efficacy in the treatment of intrahepatic cancers, its usefulness is limited by the low dose that can be tolerated. The dose limiting toxicity is referred to as Radiation Induced Liver Disease (RILD). The pathology of this lesion is identical to that of hepatic veno-occlusive disease (VOD) produced by other causes. This trial will assess the feasibility of whole liver radiation dose escalation utilizing heparin prophylaxis for RILD and alteplase (recombinant tissue-type plasminogen activator, rt-PA) to actively manage RILD should it occur. This strategy has been used successfully to treat hepatic VOD following bone marrow transplant.